MARGARET Thatcher has reached her final resting place as her ashes were buried today in the grounds of the Royal Hospital Chelsea.

Sir Mark Thatcher stood by and placed a rose on his mother's headstone

Britain's first - and so far only - female Prime Minister died aged 87 on April 8, with her funeral taking place nine days later.

While more than 2,300 mourners attended that service in St Paul's Cathedral, only a small group of family and close friends attended today's service in London.

A headstone bearing the simple inscription "Margaret Thatcher 1925 - 2013" was then fixed on top of her final resting place in the leafy grounds of the hospital.

Twelve Chelsea pensioners dressed in their distinctive scarlet coats and tricorne hats formed a guard of honour as her ashes were placed alongside those of her husband Sir Denis, who died in 2003.

The cover of the order of service for the interment of Margaret Thatcher's ashes

Carol Thatcher prepares to lay a rose on her mother's headstone

Prayers were said by hospital chaplain the Reverend Richard Whittington as her family members comforted one another.

Among the small group of mourners was Lady Thatcher's former private secretary Lord Powell and Lord Bell, her former political adviser.

Her son, Sir Mark, accompanied by his wife Sarah, and his twin sister Carol then took it in turns to place a single red rose alongside the casket, each pausing in front of it for a moment's reflection afterwards.

Carol, who wore a cream-coloured jacket and black trousers, hid her eyes behind large sunglasses as she comforted Cynthia Crawford, who was Lady Thatcher's personal assistant for more than 30 years.

Most mourners wore black at the private service held in All Saints Chapel in the hospital's Margaret Thatcher Infirmary, which she opened in 2009.

Prayers were said while music was provided by the chapel choir who sang Po Atarau, a traditional Maori song of goodbye in recognition of Lady Thatcher's family connections with New Zealand.

Mark Thatcher says his farewells to his mother

Lady Thatcher - the longest-serving prime minister of the 20th century - built up a strong relationship with the Royal Hospital Chelsea during the last 10 years of her life and her final resting place was chosen by her.

After her death, her family asked that donations be made to the hospital instead of flowers.

Fourteen Chelsea Pensioners also lined the steps as her coffin was carried into St Paul's Cathedral at her funeral on April 17.

The headstone was made by the Cardozo Kindersley Workshop in Cambridge and is made out of Hopton Wood, a type of limestone quarried in Derbyshire.

The wooden casket, which was placed into the ground by Mr Whittington, bears a brass plaque with her name on it.

Her ceremonial funeral with full military honours was attended by the Queen, Prime Minister David Cameron and dignitaries from 170 countries around the globe.

Thousands also lined the streets of London to pay their respects as the coffin bearing her body was brought in procession to the cathedral on a gun carriage drawn by six black horses.

A private cremation was later held at Mortlake Crematorium in south-west London.

Lady Thatcher became MP for Finchley in 1959 and was Conservative prime minister between 1979 and 1990.

The Iron Lady's passing led to some of her detractors holding "death parties" across the country and abroad.

But fears that the funeral would be disrupted by demonstrations did not materialise, despite some booing from protesters who turned their backs as the coffin passed and anti-Thatcher banners along the route.

There were no protests during today's internment, which was not publicised.